API RP38

Media used for the detection of Sulfate Reducing Bacteria (SRB). This media is made under strict anaerobic conditions inside an anaerobic chamber. As Sulfate Reducing Bacteria grow and metabolize in the media, they will reduce sulfate to sulfide. This biogenic sulfide then reacts with the iron nail and the dissolved iron in the API media creating a black precipitate (Iron Sulfide). This black precipitate indicates that the vial is positive for SRB.

False Positive: If the sample fluid injected into the vial contains a significant concentration of dissolved sulfide, the first one to two vials in the dilution series may turn black. Vials should be recorded as false positives if immediately, or within an hour, these vials develop a black precipitate.
Physical Characteristics: This anaerobic media is clear in color and contains an iron nail.